Process of expanding the cross sections of spun-silk yarn



profitably treated be made permanent.

UNITE- sT rs PATET. osric.

sai or-i1 SAKANE, on KAMIKYo-KU, JAPAN;

rnoonss or nxrannme rnn cnoss snor'rons or SPUN-SILK YARN.

1,11s,1es.

No Drawing.

To all whom it may concern Be it known that I, SEIIoHI SAKANE, a subjectof the Emperor of Japan, residing at No. 370 Motoshinnyodo-cho,Kamikyo-ku, Kyoto, Japan, have invented new and useful Improvements in aProcess of Expanding the Cross Sections of Spun-Silk which the followingis a specification.

This invention relates to a process of expanding the cross section of aspun-silk yarn by counter twisting the said yarn and steaming it. It hasfor its object to make elastic and soft woolly yarn of spun-silk.

The expression spun-silk is used here in a broad sense; it is used tomean not only ordinary silk that is spun but those of mandarin silks,Japanese oak silks, Chinese oak silks and the like. Silk yarn containingcotton or woollen portions may also be by this new process.

To describe further, to treat twisted single yarn, it is at first heatedin dry or wet state for twenty or thirty minutes, so that the curlingofsilk fibres in the said yarn may Where the yarn has been alreadyheated 'in a previous treatment, such for instance as bleaching,scouring or dyeing so that the curling of the silk. fibres has becomepermanent, the preparatory treatment above described may be dispensedwith.

The yarn thus treated after being dried, is then counter twisted, by anysuitable twisting machine in order to untwist about a half or one thirdof the total number of twists of the yarn. After untwisting, the silkfibres of the yarn become separated one from the other, therebyexpanding the cross section of the yarn.

Next the yarn is reeled on a swift and made into a hank by any suitablemeans such, for instance, as by winding it loosely on a pair of parallelbars. The hank is then steamed so as to prevent the yarn from retwistingbut is left free to shrink. In about five minutes of steaming, the silkfibres are permanently set in their separated condition and,consequently, the cross section of the treated yarn gets larger and theyarn becomes elastic, soft and woolly. It looks like woollen yarn but ismore lustrous.

Doubled yarn may be treated in the same way. When it is steamed andcounter twisted, the single yarns of which the twine is Yarn, of

Specification of Letters Patent. Patgntgd Ap 18, 1922.

Application filed December a, 1920. Serial No. 429,153.

made and the silk fibres in the single yarns respectively separatethemselves from one other, thereby expanding the cross section of thedoubled yarn. The single yarns and theirfibres are permanently set inseparated condition in a succeeding steam-treatment.

Instead of the preparatory steaming and untwistlng in the process ofabove mentioned, another method may be used for doubled yarn. Singleyarns, of which doubled yarn 1s to be made, are first twisted in arequired number of filatures, and then they are twined by a doublingmachine so as to produce a number of twists corresponding to about halfthe number of the filatures. For ex ample, when two single yarns of.spun-silk ber of twists or filatures of-the single yarns 1s 472 permeter in the metric system, while the corresponding number of twists is425 per meter. In the present method, the 'num ber of twists is reducedto about from 200 to 300 per meter, so that the tendency of the singleyarns to further twist is the same as yarn of 120 ply are to be doubled,the numwhen a twisted yarn is untwisted-by the counter twisting abouthalf of the total number of twists of the twistedyarn, and subjectingthe yarn to steam-treatment while keeping said yarn free to shrink butpreventing it from twisting back.

3. The process of expanding the cross section of twisted yarn whichconsists in tw1st-.

ing single yarns, doubling said yarns so'as to produce a number oftwists corresponding to approximately half the total number of twists orfilatures of the single yarns, and subjecting the yarn tosteam-treatment, while keeping the yarn free to shrink but preventing itfrom twisting.

sEnoHI SAKANE.

